REST API refers to a programming paradigm for web applications. There is no explicit standard. There are five qualities that a REST service must have to be in. Previously we discussed about API or Application programming interface in details for the starters. So, in this article we will say about this REST API.
Principles of REST API
Basically the idea behind REST API is that a web address represents a single page contents as a result of a server-side action such as displaying a list after a search. In practice REST API usually helps to store URLs from the web browser as a bookmark and call at any later time. In theory REST API requires all information needed by an application in the request. It identifies the URI of the resource while in the HTTP header information, such as access method (GET, PUT), return format or authentication may be included. In its pure form, REST or REST API can be used for websites and web services that do not require authentication or the other means.
Principles and Implementations of REST and REST API

There are five qualities that a REST service thereby a REST API call must have to be in, these are :
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- Addressability
- Different representations
- Statelessness
- Uniform interface
- Cacheability
REST and REST API standardizes the interface between systems in a manageable way. For the implementation of the REST API the architectural style mostly used as application layer protocol is mainly HTTP.
GET : Calls for the specified resource from the server.
POST : adds a new (sub-) resource under the specified resource.
PUT : The specified resource is created or changed.
PATCH : A portion of the specified resource is changed.
DELETE : Deletes the specified resource.
HEAD : Requires metadata to a resource from the server.
OPTIONS : Examines what methods are available on a resource.
